The batch ALD platforms have a wide range of applications with various requirements and constraints that demands a flexible architecture. Platform requirements include wafer preheating, post cooling, preheat & post cool, throughput from 30 wph to 270 wph, high vacuum loadlocks, and numerous other specifications. With the numerous parameters and individual apparatus that make up the platform, it can be challenging to provide functionality with low entitlement cost.
Some ALD platforms currently provide standard and active wafer cooling capable loadlocks. The high temperature processes (>450° C.) require the wafer be preheated prior to being placed on the process chamber susceptor. In a conventional system, a room temperature wafer preheated in the process chamber for as long as 3 minutes. This cost valuable processing time and significantly reduces system throughput for shorter processes.
Current products employ numerous methods to heat single wafers either in a loadlock or a separate process chamber. However, when using a batch ALD platform with, for example, six wafers, heating single wafers in a separate chamber or loadlock would not provide sufficient throughput. Single wafer loadlock cycles are too slow to the meet the wafer exchange budget. Additionally, the transfer chambers used with batch processing chambers may not have another facet for a heating chamber. Even if another facet were available, vacuum robots cannot produce satisfactory throughput with the additional handoff location. Accordingly, there is a need in the art for apparatus and methods of preheating wafers for batch processing including robots capable of producing the sufficient throughput.